Magnetic fields in the early Universe

There is increasing evidence that intense magnetic fields exist at large redshifts. They could arise after galaxy formation or in very early processes, such as inflation or cosmological phase transitions, or both. Early co-moving magnetic strengths in the range 1-10 nG could be present at recombination. The possibilities to detect them in future CMB experiments are discussed, mainly considering their impact in the anisotropy spectra as a result of Faraday rotation and Alfven waves. Magnetic fields this magnitude could also have a non-negligible influence in determining the filamentary large scale structure of the Universe.